Conventionally, as absorbent articles that absorb certain fluid such as menstrual blood, absorbent articles including a main body section that absorbs fluid and a surface structure partially fixed to the surface of the main body section, in which the back face of the main body section includes a fluid-impermeable sheet made of polyethylene or the like in order to prevent leakage of the fluid are known (refer to JP-A-2003-79662, for example). Regarding the above fluid, the manner of the flow varies depending on the posture of the user when wearing the absorbent article. For example, in the case where the body is in a standing state, fluid flows in the vertical direction and is often directly absorbed by the absorbent article. However, in a state the body is lying down during sleep or the like, discharged fluid may flow down the body, more specifically, the bodily groove, and flow towards the rear side of the user. Accordingly, in order to cause fluid to be absorbed without leakage at any time, there is needed an absorbent article that is large enough to cover an area from a position covering a front side of a fluid discharge portion to a position covering the bodily groove, such as the vicinity of the coccyx.
Further, in recent years, in order to prevent displacement, an absorbent article has been devised including a surface structure that is disposed along the front-and-rear direction of the body in use, and that has a front side fixed to a main body section and a rear side separable from the main body section, and the absorbent article is worn so that the rear side portion of the surface structure is in the groove between the buttocks. At the time of using the absorbent article, the user pulls up the rear end side of the surface structure rearward, thereby disposing the surface structure in the groove between the buttocks.